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4-108M fuel filter bleeding

jjgurley

New member
There was a thread with a similar issue, but it missed the mark slightly, so I'll try again.

My new-to-me 1984 4-108M has a final fuel filter that is a little different than that shown in my manual. It is an exposed cartridge type, has banjo connections downstream rather than compression fittings, and most importantly, doesn't have a "bleed screw". The manual warns that you should open the bleed screw "and not the tank return" so I was a little hesitant to go spelunking.

Anyway, after changing my fuel filter, I had to use the injector pump bleed screw to get the engine running again, but because it's on the opposite side of the engine from the lift pump primer, I was working blind and probably put a lot more diesel into the bilge than necessary. Simply bleeding the cartridge would have been much faster.filter.JPG

The boat is also fitted with an electric fuel pump with a toggle switch and crossover fuel lines, which I assume is intended to address this problem, but the pump didn't appear to work. Either the pump is shot or the wiring is fouled up.
 
If there is no bleed screw on top loosen the banjo bolt which holds the fuel line going to the inj. Pump inlet (rear of inj. Pump) pump until all air bubbles stop, tighten the bolt than pump a few more times . It may still be necessary to bleed at the inj pump.
Charlie w.
 
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